Quantification of the major urinary metabolite of PGE2 by a liquid chromatographic/mass spectrometric assay: determination of cyclooxygenase-specific PGE2 synthesis in healthy humans and those with lung cancer.

Abstract

Prostaglandin (PG)E2 is a major cyclooxygenase (COX) product that is important in human physiology and pathophysiology. Quantification of systemic PG production in humans is best assessed by measuring excreted urinary metabolites. Accurate and easy-to-perform assays to quantify the major urinary metabolite of PGE2, 11alpha-hydroxy-9,15-dioxo-2,3,4,5-tetranor-prostane-1,20-dioic acid (PGE-M), do not exist. We now report the development of a robust and facile method to measure urinary PGE-M excretion in humans using stable isotope dilution techniques employing liquid chromatography/tandem mass spectrometry (LC/MS/MS). Concentrations of the metabolite in urine from healthy humans are nearly twofold greater in men than in women (10.4+/-1.5 vs. 6.0+/-0.7 ng/mg creatinine). Levels of PGE-M in healthy humans are suppressed significantly not only by the nonselective COX inhibitor ibuprofen but also by the COX-2 selective inhibitor rofecoxib, suggesting that the majority of PGE2 formed in vivo is derived from COX-2. Increased COX-2 expression and increased PGE2 production are associated with malignancy. Levels of PGE-M were found to be greatly increased in humans with unresectable non-small cell cancer of the lung, and this increase is dramatically reduced by administration of the COX-2 inhibitor celecoxib, implying that COX-2 contributes significantly to the overproduction of PGE2. In summary, quantification of PGE-M using LC/MS/MS provides a facile and accurate method to assess PGE2 formation in human physiological and pathophysiological processes.

• Authors: Laine J Murphey, Myles K Williams, Stephanie C Sanchez, Loretta M Byrne, Ildiko Csiki, John A Oates, David H Johnson, Jason D Morrow
• Journal: Analytical biochemistry (Anal Biochem) Vol. 334 Issue 2 Pg. 266-75 (Nov 15 2004) ISSN: 0003-2697 [Print] United States
• PMID: 15494133 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Cyclooxygenase 2 Inhibitors
• Cyclooxygenase Inhibitors
• Membrane Proteins
• Prostaglandins
• 7-hydroxy-5,11-dioxotetranorprostane-1,16-dioic acid
• Cyclooxygenase 2
• PTGS2 protein, human
• Prostaglandin-Endoperoxide Synthases
• Dinoprostone

Topics

• Carcinoma, Non-Small-Cell Lung (metabolism, urine)
• Case-Control Studies
• Chromatography, Liquid
• Cyclooxygenase 2
• Cyclooxygenase 2 Inhibitors
• Cyclooxygenase Inhibitors (pharmacology)
• Dinoprostone (biosynthesis, chemistry, metabolism)
• Health
• Humans
• Lung Neoplasms (metabolism, urine)
• Membrane Proteins
• Molecular Structure
• Prostaglandin-Endoperoxide Synthases (metabolism)
• Prostaglandins (chemistry, metabolism, urine)
• Reproducibility of Results
• Spectrometry, Mass, Electrospray Ionization